From DE 102 00 533 A1 a method and a device for controlling an internal combustion engine are known. The internal combustion engine has a manifold from which an intake tube extends to an intake of a cylinder of the internal combustion engine. A gas inlet valve is disposed at the intake of the cylinder. An intermittent charge valve is disposed upstream of the gas inlet valve in the intake tube. The intake tube is open or closed, depending on the switching position of the intermittent charge valve. Furthermore, an injection valve is provided which meters the fuel. The rapidly switching intermittent charge valves which are assigned to each cylinder are closed during the first section of the intake sequence so that a high negative pressure can build up. After approximately half of the intake sequence, the intermittent charge valve—the rapidly switching cross-sectional switch—is opened suddenly so that the negative pressure generated in the cylinder during the first section of the intake sequence generates a very high velocity of flow of the intake air/fuel mixture. The intake air column flowing very rapidly in to the combustion chamber of the cylinder of the internal combustion engine produces, in the range of low to moderate revolutions of the internal combustion engine, significant supercharging effects because of the better filling characteristics of the respective combustion chamber.
More stringent legal provisions with regard to the emissions, especially exhaust-gas emissions, of motor vehicles require that these be kept low if possible in all operating states of the internal combustion engine. Very high emissions are in principle generated in particular when the internal combustion engine is started up. This can be attributed to the fact that the internal combustion engine has not yet reached its operating temperature, and consequently fuel is deposited on the wall of the intake tube and/or the internal walls of the cylinders. The consequence of this is that a desired air/fuel ratio in the cylinder is optionally set defectively, which can lead to increased exhaust-gas emissions. In addition, the injected fuel vaporizes less well before the operating temperature is reached, which can also result in an impaired combustion process with increased waste-gas emissions, for example NOX, CO and CH emissions, as a consequence. This affects both internal combustion engines having injection valves which are disposed on the intake tubes and meter the fuel into the intake tubes and internal combustion engines in which the injection valves are disposed in the cylinder head and meter the fuel directly into the combustion chamber of the cylinder.
From U.S. Pat. Nos. 5,671,708 and 5,722,365 methods are known for controlling an internal combustion engine comprising an air-flow control valve which has a hole in its leaf and which thus enables an air flow through the intake tube even in its closed position. The air-flow control valve is closed during the entire start-up operation of the internal combustion engine, with the result that air is sucked into the cylinders of the internal combustion engine solely through the hole in the leaf.